System and method for compensation of turbo lag in hybrid vehicles

ABSTRACT

A system and method for compensation of turbo lag in hybrid vehicles is disclosed. The system identifies a zero boost power limit of the engine and a torque curve power limit. A turbocharger dynamic model is then developed based on measurements of the input engine power and the output max available engine power. The model is used to determine an overall propulsion power limit based on the combination of the engine and motor in operation. A power request by the driver may then be limited to the overall propulsion power limit to compensate for the effect of the turbocharger when propelling the vehicle using both the engine and motor and better simulate the engine-only response.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application No. 15,657,875filed Jul. 24, 2017, which is a continuation of U.S. application Ser.No. 14/838,403 filed Aug. 28, 2015, which is a continuation ofInternational Application No. PCT/US2014/020417 filed Mar. 4, 2014,which claims the benefit of U.S. Provisional Application No. 61/782,962filed Mar. 14, 2013, which are hereby incorporated by reference in theirentirety.

BACKGROUND

Hybrid vehicles typically have a combustion engine and an eMachine whichcan act as both an electric motor and a generator. During braking, suchvehicles are capable of capturing and storing the braking energy in abattery for later use in propelling the vehicle. This process iscommonly referred to as regenerative braking. Some hybrid vehicles areconfigured to use the energy stored in the battery to boost propulsionperformance beyond the capabilities of the engine acting alone. However,it is generally preferred to instead operate the vehicle in a mannerwhich simulates the propulsion response of the engine only. This assuresthe operator will experience a response which is consistent withnon-hybrid vehicles.

In order to achieve this engine-only simulated response when using boththe electric motor and engine to propel the vehicle, many hybridvehicles reduce the output of the engine by that of the hybrid motor tomatch the equivalent engine-only output. This method is typicallysatisfactory for normally aspirated engines, since the torque producedby the engine at a given rotational engine speed (rpm) is relativelyconstant over time.

In turbocharged engines, however, the power generated by the engine maychange with time due to the effect of the turbocharger. A turbochargeruses engine exhaust gases to drive a turbine wheel. A shaft connects theturbine wheel to a compressor wheel in the air intake path of theengine. Therefore, as the turbine wheel is driven by the flow of exhaustgas, the compressor wheel also spins and compresses the air to theintake of the engine. As the intake air is compressed over time (andincreasing amounts of fuel are added), the power generated by the enginealso increases. As the engine output increases and more exhaust gasesare generated, the turbine and compressor wheels spin faster, therebyincreasing the power generated by the engine still further. However,because the turbocharger requires time to overcome the inertia of thecompressor wheel and begin to spin, there is a delay in the deliveredpower response. This effect is commonly referred to as turbo lag andgives the operator a feeling of gradual building of engine power.

The turbocharger effect prevents the simple substitution of electricalpower for engine power in a hybrid vehicle where an engine-onlyequivalent response is desired. This is because as electrical power fromthe motor replaces engine power, the engine power generation capacity isdiminished even further due to the loss of the turbo effect. In otherwords, if a portion of the engine power is substituted by powergenerated by the electric motor, the resulting combination output willnot match that of the equivalent output if the engine had been actingalone.

Thus, there is a need for improvement in this field.

SUMMARY

The system and method described herein addresses the issues mentionedabove. In a general sense, the disclosed system monitors the engineoutput over time to determine a dynamic model of the turbochargereffect. The system then applies the model to determine a propulsionpower limit for the combined output of the engine and electric motorwhich will simulate the response of the engine acting alone.

According to one aspect of the disclosure, a method of operating ahybrid vehicle is disclosed, comprising using a vehicle controller,determining a zero boost power limit of an engine of the hybrid vehicle,said engine including a turbocharger, determining a torque curve powerlimit of the engine, the torque curve power limit based upon the maximumavailable power when the turbocharger is operating at a predeterminedlevel, monitoring a current power of the engine and a maximum availablepower of the engine when the maximum available power is between the zeroboost power limit and the torque curve power limit, determining adynamic response model of the engine based on said monitoring, the modelproviding an estimation of the engine output power over time as theturbocharger increases in speed, receiving a driver output torquerequest, and operating the hybrid vehicle such that the collectiveoutput power of the engine and an eMachine of the hybrid vehicle isautomatically limited to a turbo-equivalent power limit based on saidmodel, said-turbo equivalent power limit representing the power limit ofthe engine acting alone.

According to another aspect, a hybrid system is disclosed, comprising anengine having a turbocharger, an engine controller operatively coupledto the engine, an eMachine, a hybrid controller operatively coupled tothe eMachine and in communication with the engine controller. The hybridcontroller is configured to determine a zero boost power limit of theengine, receive torque curve information from the engine controller,determine a torque curve power limit of the engine from the torque curveinformation, monitor a current power of the engine and a maximumavailable power of the engine when the maximum available power isbetween the zero boost power limit and the torque curve power limit,determine a dynamic response model of the engine based on themonitoring, the model providing an estimation of the engine output powerover time as the turbocharger increases in speed, receive a driveroutput torque request from the engine controller, and operate the hybridvehicle such that the collective output power of the engine and aneMachine of the hybrid vehicle is automatically limited to aturbo-equivalent power limit based on the model, the turbo-equivalentpower limit representing the power limit of the engine acting alone.

Further forms, objects, features, aspects, benefits, advantages, andembodiments of the present invention will become apparent from adetailed description and drawings provided herewith.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a diagrammatic view of one example of a hybridsystem.

FIG. 2 illustrates a general diagram of an electrical communicationsystem in the FIG. 1 hybrid system.

FIG. 3 illustrates a method for operating the hybrid system of FIG. 1according to one embodiment.

DETAILED DESCRIPTION

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings, and specific language will be used to describe the same.It will nevertheless be understood that no limitation of the scope ofthe invention is thereby intended. Any alterations and furthermodifications in the described embodiments and any further applicationsof the principles of the invention as described herein are contemplatedas would normally occur to one skilled in the art to which the inventionrelates. One embodiment of the invention is shown in great detail,although it will be apparent to those skilled in the relevant art thatsome features not relevant to the present invention may not be shown forthe sake of clarity.

The reference numerals in the following description have been organizedto aid the reader in quickly identifying the drawings where variouscomponents are first shown. In particular, the drawing in which anelement first appears is typically indicated by the left-most digit(s)in the corresponding reference number. For example, an elementidentified by a “100” series reference numeral will first appear in FIG.1, an element identified by a “200” series reference numeral will firstappear in FIG. 2, and so on. With reference to the Specification,Abstract, and Claims sections herein, it should be noted that thesingular forms “a”, “an”, “the”, and the like include plural referentsunless expressly discussed otherwise. As an illustration, references to“a device” or “the device” include one or more of such devices andequivalents thereof.

FIG. 1 shows a diagrammatic view of a hybrid system 100 according to oneembodiment. The hybrid system 100 illustrated in FIG. 1 is adapted foruse in commercial-grade trucks as well as other types of vehicles ortransportation systems, but it is envisioned that various aspects of thehybrid system 100 can be incorporated into other environments. As shown,the hybrid system 100 includes an engine 102, a hybrid module 104, anautomatic transmission 106, and a drive train 108 for transferring powerfrom the transmission 106 to wheels 110. In one example, the engine 102comprises an internal combustion engine having a turbocharger. Theturbocharger includes a turbine wheel in the exhaust path of the engine.A shaft connects the turbine wheel to a compressor wheel in the airintake path of the engine. As the turbine wheel is driven by the flow ofexhaust gas from the engine, the compressor wheel also spins andcompresses the air to the intake of the engine, thereby increasing thepower generating capacity of the engine. The hybrid module 104incorporates a rotating electrical machine, commonly referred to as aneMachine 112, and a clutch 114 that operatively connects and disconnectsthe engine 102 from the eMachine 112 and the transmission 106.

The hybrid module 104 is designed to operate as a self-sufficient unit,that is, it is generally able to operate independently of the engine 102and transmission 106. In particular, its hydraulics, cooling andlubrication do not directly rely upon the engine 102 and thetransmission 106. The hybrid module 104 includes a sump 116 that storesand supplies fluids, such as oil, lubricants, or other fluids. Tocirculate the fluid, the hybrid module 104 includes a mechanical pump118 and an electrical (or electric) pump 120. With this combination ofboth the mechanical pump 118 and electrical pump 120, the overall sizeand, moreover, the overall expense for the pumps is reduced.

The hybrid system 100 further includes a cooling system 122 that is usedto cool the fluid supplied to the hybrid module 104 as well as thewater-ethylene-glycol (WEG) to various other components of the hybridsystem 100 which will be described later in further detail. Looking atFIG. 1, the cooling system 122 includes a fluid radiator 124 that coolsthe fluid for the hybrid module 104. The cooling system 122 furtherincludes a main radiator 126 that is configured to cool the antifreezefor various other components in the hybrid system 100. A cooling fan 128flows air through both fluid radiator 124 and main radiator 126. Acirculating or coolant pump 130 circulates the antifreeze to the mainradiator 126.

The eMachine 112 in the hybrid module 104, depending on the operationalmode, at times acts as a generator and at other times as a motor. Whenacting as a motor, the eMachine 112 draws alternating current (AC). Whenacting as a generator, the eMachine 112 creates AC. An inverter 132converts the AC from the eMachine 112 and supplies it to an energystorage system 134. The eMachine 112 in one example is an HVH410 serieselectric motor manufactured by Remy International, Inc. of Pendleton,Ind., but it is envisioned that other types of eMachines can be used. Inthe illustrated example, the energy storage system 134 stores the energyand resupplies it as direct current (DC). When the eMachine 112 in thehybrid module 104 acts as a motor, the inverter 132 converts the DCpower to AC, which in turn is supplied to the eMachine 112. The energystorage system 134 in the illustrated example includes three energystorage modules 136 that are connected together, preferably in parallel,to supply high voltage power to the inverter 132. The energy storagemodules 136 are, in essence, electrochemical batteries for storing theenergy generated by the eMachine 112 and rapidly supplying the energyback to the eMachine 112. The energy storage modules 136, the inverter132, and the eMachine 112 are operatively coupled together through highvoltage wiring as is depicted by the line illustrated in FIG. 1. Whilethe illustrated example shows the energy storage system 134 includingthree energy storage modules 136, it should be recognized that theenergy storage system 134 can include more or less energy storagemodules 136 than is shown. Moreover, it is envisioned that the energystorage system 134 can include any system for storing potential energy,such as through chemical means, pneumatic accumulators, hydraulicaccumulators, springs, thermal storage systems, flywheels, gravitationaldevices, and capacitors, to name just a few examples.

High voltage wiring connects the energy storage system 134 to a highvoltage tap 138. The high voltage tap 138 supplies high voltage tovarious components attached to the vehicle. A DC-DC converter system140, which includes one or more DC-DC converter modules 142, convertsthe high voltage power supplied by the energy storage system 134 to alower voltage, which in turn is supplied to various systems andaccessories 144 that require lower voltages. As illustrated in FIG. 1,low voltage wiring connects the DC-DC converter modules 142 to the lowvoltage systems and accessories 144.

The hybrid system 100 incorporates a number of control systems forcontrolling the operations of the various components. For example, theengine 102 has an engine control module 146 that controls variousoperational characteristics of the engine 102 such as fuel injection andthe like. A transmission/hybrid control module (TCM/HCM) 148 substitutesfor a traditional transmission control module and is designed to controlboth the operation of the transmission 106 as well as the hybrid module104. The transmission/hybrid control module 148 and the engine controlmodule 146 along with the inverter 132, energy storage system 134, andDC-DC converter system 140 communicate along a communication link as isdepicted in FIG. 1. In a typical embodiment, the transmission/hybridcontrol module 148 and engine control module 146 each comprise acomputer having a processor, memory, and input/output connections.Additionally, the inverter 132, energy storage system 134, DC-DCconverter system 140, and other vehicle subsystems may also containcomputers having similar processors, memory, and input/outputconnections.

To control and monitor the operation of the hybrid system 100, thehybrid system 100 includes an interface 150. The interface 150 includesa shift selector 152 for selecting whether the vehicle is in drive,neutral, reverse, etc., and an instrument panel 154 that includesvarious indicators 156 of the operational status of the hybrid system100, such as check transmission, brake pressure, and air pressureindicators, to name just a few.

FIG. 2 shows a diagram of one example of a communication system 200 thatcan be used in the hybrid system 100. While one example is shown, itshould be recognized that the communication system 200 in otherembodiments can be configured differently than is shown. Thecommunication system 200 is configured to minimally impact the controland electrical systems of the vehicle. To facilitate retrofitting toexisting vehicle designs, the communication system 200 includes a hybriddata link 202 through which most of the various components of the hybridsystem 100 communicate. In particular, the hybrid data link 202facilitates communication between the transmission/hybrid control module148 and the shift selector 152, inverter 132, the energy storage system134, the low voltage systems/accessories 144, and the DC-DC convertermodules 142. Within the energy storage system 134, an energy storagemodule data link 204 facilitates communication between the variousenergy storage modules 136. However, it is contemplated that in otherembodiments the various energy storage system modules 136 cancommunicate with one another over the hybrid data link 202. With thehybrid data link 202 and the energy storage module data link 204 beingseparate from the data links used in the rest of the vehicle, thecontrol/electrical component of the hybrid system 100 can be readilytied into the vehicle with minimum impact. In the illustrated example,the hybrid data link 202 and the energy storage module data link 204each have a 500 kilobit/second (kbps) transmission rate, but it isenvisioned that data can be transferred at other rates in otherexamples. Other components of the vehicle communicate with thetransmission/hybrid control module 148 via a vehicle data link 206. Inparticular, the shift selector 152, the engine control module 146, theinstrument panel 154, an antilock braking system 208, a body controller210, the low voltage systems/accessories 144, and service tools 212 areconnected to the vehicle data link 206. For instance, the vehicle datalink 206 can be a 250 k J1939-type data link, a 500 k J1939-type datalink, a General Motors LAN, or a PT-CAN type data link, just to name afew examples. All of these types of data links can take any number offorms such as metallic wiring, optical fibers, radio frequency, and/or acombination thereof, just to name a few examples.

In terms of general functionality, the transmission/hybrid controlmodule 148 receives power limits, capacity, available current, voltage,temperature, state of charge, status, and fan speed information from theenergy storage system 134 and the various energy storage modules 136within. The transmission/hybrid control module 148 in turn sendscommands for connecting the various energy storage modules 136 so as tosupply voltage to and from the inverter 132. The transmission/hybridcontrol module 148 also receives information about the operation of theelectrical pump 120 as well as issues commands to the electrical pump120. From the inverter 132, the transmission/hybrid control module 148receives a number of inputs such as the motor/generator torque that isavailable, the torque limits, the inverter's voltage, current and actualtorque speed. Based on that information, the transmission/hybrid controlmodule 148 controls the torque speed and the pump 130 of the coolingsystem. From the inverter 132, the transmission/hybrid control module148 also receives a high voltage bus power and consumption information.The transmission/hybrid control module 148 also monitors the inputvoltage and current as well as the output voltage and current along withthe operating status of the individual DC-DC converter modules 142 ofthe DC-DC converter system 140. The transmission/hybrid control module148 also communicates with and receives information regarding enginespeed, engine torque, engine power, engine power limit, torque curveinformation, and driver requested output torque, to name a few, from theengine control module 146 and in response controls the torque and speedof the engine 102 via the engine control module 146.

As discussed above, it may be advantageous to simulate an engine-onlyresponse during operation, even when operating the vehicle with theassistance of the eMachine 112. In order to better represent such aresponse, a method for compensating for the turbo-lag effect (e.g., whenengine 102 is implemented as a turbocharged engine) will now bediscussed.

The response of a turbocharged engine may be modeled as a first orderlinear system described by the differential equation (1) below:

$\begin{matrix}{\frac{{dy}(t)}{dt} = {{- \frac{y(t)}{T}} + {{ku}(t)}}} & (1)\end{matrix}$

where u(t) is the input engine power, y(t) is the resulting output powerdue to the turbocharger, T is a time constant, and k is a gain constant.It shall be understood that equation (1) represents only one possibleturbo response model and that any model of turbocharger dynamics knownin the art may be used in block 304. Furthermore, the first order linearsystem of equation (1) can be expressed in discrete time as equation (2)below:

y([n+1]T _(s))=αy(n T _(s))+k(1−a)u(nT _(s))  (2)

where

$\alpha = e^{- \frac{T_{s}}{T}}$

and T_(s) is the discrete sample time, and n is the current iteration.Therefore, y([n+1]T_(s)) is the output value of the n+1 iteration,y(nT_(s)) is the output value of the n iteration, and u(nT_(s)) is theinput value of the n iteration.

The engine control module 146 is continuously broadcasting the currentpower, power limit, torque curve, and the driver requested output torqueto the transmission/hybrid control module 148. The engine control module146 determines these values based on data received from various sensorswithin the system 100 and other stored data. For example, the currentengine power may be determined by the actual engine torque (based onknown fueling rate to torque relationships for the engine) multiplied bythe current engine shaft speed received from a speed sensor on theengine output shaft. The engine power limit is the current power thatthe engine could supply if requested. The torque curve is a data tablewhich equates various engine speeds to the amount of torque that couldbe supplied by the engine at those speeds if the turbo was already spunup to a given speed. The driver requested output torque is determined bythe engine control module 146 based on the position of an acceleratorpedal or other driver input device. It shall be understood that thevalues being received and calculated by the engine control module 146may also be received and calculated directly by the transmission/hybridcontrol module 148. The engine control module 146 and thetransmission/hybrid control module 148 may be implented as separateunits or integrated into a single controller or housing.

If the input u(nT_(s)) of equation (1) is taken to be the current enginepower and the output y(nT_(s)) is taken to be the engine power limit,then as long as the engine is operating between an identified zero boostpower limit and the torque curve limit, the constants k and a can beidentified. In other words, since the input and output of the equation(1) are being broadcast by the engine and are therefore known, theremaining unknown k and a constants can be determined. The process fordetermining the k and a constants based on the known input and outputmay be implemented using adaptive infinite impulse response (IIR)filtering, such as the Steiglitz-McBride algorithm, although othermethods known in the art may also be used. The determination of theconstants k and a may be run continuously in order to constantly improvethe accuracy of the turbo response model over time. To determine thezero boost power limit, the power limit broadcast by the engine controlmodule 146 may be monitored while the engine is operating at low power,such as during an idle condition.

The identified constants k and a can be used to determine an overallturbo-equivalent power limit. The turbo-equivalent power limit is thelimit that will be imposed on the combined output power of the engine102 and eMachine 112 when both the engine 102 and eMachine 112 arecontributing to the power being fed to the transmission 106. In thisway, response of the vehicle perceived by the vehicle will simulate thatof the turbocharged engine acting alone.

FIG. 3 represents a process for implementing the above method using thehybrid system 100. The process begins at start point 302 where thetransmission/hybrid control module 148 determines that the engine 102has attained an idle speed for a predetermined time (304). Thetransmission/hybrid control module 148 determines the zero boost powerlimit by averaging the values for maximum available torque received fromthe engine control module 146 over the idle time period and multiplyingthe average by the current engine speed. This provides an estimatedlower limit for the engine output power when the turbocharger is notcontributing to the output.

At stage 306, the transmission/hybrid control module 148 determines thetorque curve power limit. As discussed above, the transmission/hybridcontrol module 148 receives the torque curve data (available torques atvarious speeds) from the engine control module 146. Alternatively, thetorque curve data may be stored in memory of the transmission/hybridcontrol module 148. To determine the torque curve power limit, thetransmission/hybrid control module 148 retrieves the maximum torqueavailable at the current engine speed from the torque curve data, andmultiplies the result by the current engine speed.

Continuing to stage, 308, the transmission/hybrid control module 148monitors the values for current engine power, and current maximumavailable engine power being broadcast by the engine control module 146.As discussed above, at times when the current maximum available enginepower is between the zero boost power limit (from stage 304) and thetorque curve power limit (from stage 306), the observed data is used todetermine the constants k and a of the turbocharger response equation(2). The stages 304, 306, and 308 above may be run continuously andindependent of the remaining stages to adaptively identify and updatethe values being determined.

At stage 310, the transmission/hybrid control module 148 determines thecurrent engine power being output by the engine 102. Thetransmission/hybrid control module 148 receives the actual engine torqueand the current engine speed from the engine control module 146, andmultiplies these values to determine the current engine power.

At stage 312, the transmission/hybrid control module 148 determines thecurrent eMachine 112 output power being delivered to the transmission106. To determine this, the transmission/hybrid control module 148multiplies the eMachine 112 motor torque (which is known by thetransmission/hybrid control module 148) by the eMachine 112 speed(received from a speed sensor on a shaft of the eMachine 112).

At stage 314, the transmission/hybrid control module 148 determines atotal propulsion power being delivered to the transmission 106 by addingthe current engine power from stage 310 to the current eMachine 112power from stage 312.

At stage 316, along with the known constants k and a, the totalpropulsion power is applied as input u(nT_(s)) to equation (2). Thisgives the resulting turbo equivalent power limit, y([n+1]T_(s)), for thepropulsion power of the combination of engine 102 and eMachine 112.

At stage 318, the transmission/hybrid control module 148 compares theturbo-equivalent power limit from stage 314 to the zero boost powerlimit from stage 304. If the turbo-equivalent power limit is less thanthe zero boost power limit, then the turbo-equivalent power limit is setto the zero boost power limit. If not, the turbo-equivalent power limitremains unchanged.

At stage 320, the transmission/hybrid control module 148 compares theturbo-equivalent power limit from stage 318 to the torque curve powerlimit from stage 306. If the torque curve power limit is less than theturbo-equivalent power limit, then the turbo-equivalent power limit isset to the torque curve power limit. If not, the turbo-equivalent powerlimit remains unchanged. At this point, the turbo-equivalent power limitis characterized as a total propulsion power limit. The stages 310-320above may also be run continuously and independent of the other stagesto adaptively identify and update the values being determined, includingtotal propulsion power limit.

At stage 322, the transmission/hybrid control module 148 determines thedriver requested output power. In one embodiment, thetransmission/hybrid control module 148 receives the driver requestedtorque (based on acceleration pedal displacement) and current enginespeed from the engine control module 146, and multiplies the values todetermine the driver requested output power.

At stage 324, the transmission/hybrid control module 148 compares thedriver requested power to the total propulsion power limit from stage320 and determines a transmission input power request value. If thedriver requested output power is less than the total propulsion powerlimit, then the input power request value will be set to a value equalto the driver requested power. However, if the driver request power ismore than the total propulsion power limit, then the transmission inputpower request will be set to a value equal to the total propulsion powerlimit.

At stage 326, the transmission/hybrid control module 148 determines theamount of power to be supplied by each of the engine 102 and theeMachine 112 in order to collectively provide a total amount of inputpower to the transmission which is equal to the transmission input powerrequest value from stage 324. Any combination of power levels of theengine 102 and eMachine 112 may be used as long as the total combinedpower is equal to the transmission input power request. This ensuresthat the response felt by the driver is limited to that of theturbocharged engine acting alone

It shall be understood that the process of the FIG. 3 may be repeatedindefinitely to adaptively update the values being received, evaluatedand determined. Additionally, it shall be understood that certain stepsof the process may be performed or repeated individually, independent ofthe other steps as discussed above.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges, equivalents, and modifications that come within the spirit ofthe inventions defined by following claims are desired to be protected.All publications, patents, and patent applications cited in thisspecification are herein incorporated by reference as if each individualpublication, patent, or patent application were specifically andindividually indicated to be incorporated by reference and set forth inits entirety herein.

1. A method of operating a hybrid vehicle using a hybrid controller,comprising: determining a zero boost power limit of an engine of thehybrid vehicle, said engine including a turbocharger; determining atorque curve power limit of the engine, said torque curve power limitbased upon the maximum available power when the turbocharger isoperating at a predetermined level; monitoring a current power of theengine and a maximum available power of the engine when the maximumavailable power is between the zero boost power limit and the torquecurve power limit; and determining a dynamic response model of theengine based on said monitoring, said model providing an estimation ofthe engine output power over time as the turbocharger increases inspeed.
 2. The method of claim 1, further comprising: receiving a driveroutput torque request; and operating the hybrid vehicle such that thecollective output power of the engine and an eMachine of the hybridvehicle is automatically limited to a turbo-equivalent power limit basedon said model, said turbo-equivalent power limit representing the powerlimit of the engine acting alone.
 3. The method of claim 1 or 2, furthercomprising: determining an actual engine torque of the engine;multiplying said actual engine torque by a current engine speed of theengine to determine a current engine power; determining an eMachinetorque of the eMachine; multiplying said eMachine torque by a currenteMachine speed of the eMachine to determine a current eMachine outputpower; adding said current engine power and said eMachine power todetermine a total propulsion power; and using the total propulsion powerto determine the turbo-equivalent power limit using the model.
 4. Themethod of any previous claim, further comprising: setting theturbo-equivalent power limit to the zero boost power limit if the zeroboost power limit is greater than said turbo-equivalent power limit. 5.The method of any previous claim, further comprising: setting theturbo-equivalent power limit to the torque curve power limit if thetorque curve power limit is less than the turbo-equivalent power limit.6. The method of any previous claim, wherein said dynamic response modelis determined by the controller using infinite impulse responsefiltering.
 7. The method of any previous claim, wherein said dynamicresponse model is represented discreetly by the equation:y([n+1]T _(s))=αy(nT _(s))+k(1−α)u(nT _(s)) where T is a constant, k isa constant, ${\alpha = e^{- \frac{T_{s}}{T}}},$ T_(s) is a discretesample time, y([n+1]T_(s)) is the turbo-equivalent output power of then+1 iteration, y(nT_(s)) is the turbo-equivalent output power value ofthe n interation, and u(nT_(s)) is the current engine power of the niteration.
 8. The method of claim 7, wherein T and k are adaptivelydetermined by infinite impulse response filtering.
 9. The method of anyprevious claim, wherein said zero boost power limit is determined bymonitoring the maximum available torque of the engine while the engineis idling.
 10. The method of claim 9, wherein said zero boost powerlimit is determined by multiplying a current engine speed by the averageof the maximum available torque of the engine when idling.
 11. A hybridsystem, comprising: an engine having a turbocharger; an enginecontroller operatively coupled to the engine; an eMachine; a hybridcontroller operatively coupled to the eMachine and in communication withthe engine controller; wherein the hybrid controller is configured to:determine a zero boost power limit of the engine; receive torque curveinformation from the engine controller; determine a torque curve powerlimit of the engine from said torque curve information; monitor acurrent power of the engine and a maximum available power of the enginewhen the maximum available power is between the zero boost power limitand the torque curve power limit; and determine a dynamic response modelof the engine based on said monitoring, said model providing anestimation of the engine output power over time as the turbochargerincreases in speed.
 12. The method of claim 11, wherein the hybridcontroller is further configured to: receive a driver output torquerequest from said engine controller; and operate the hybrid vehicle suchthat the collective output power of the engine and an eMachine of thehybrid vehicle is automatically limited to a turbo-equivalent powerlimit based on said model, said turbo-equivalent power limitrepresenting the power limit of the engine acting alone.
 13. The systemof claim 11 or 12, wherein the hybrid controller is further configuredto: receive an actual engine torque and a current engine speed from theengine controller; multiply said actual engine torque by said currentengine speed to determine a current engine power; determine an eMachinetorque of the eMachine; multiply said eMachine torque by a currenteMachine speed of the eMachine to determine a current eMachine outputpower; and add said current engine power and said eMachine power todetermine a total propulsion power; and use the total propulsion powerto determine the turbo-equivalent power limit using the model.
 14. Thesystem of any one of claims 11-13, wherein the hybrid controller isfurther configured to set the turbo-equivalent power limit to the zeroboost power limit if the zero boost power limit is greater than saidturbo-equivalent power limit.
 15. The system of any one of claims 11-14,wherein the hybrid controller is further configured to set theturbo-equivalent power limit to the torque curve power limit if thetorque curve power limit is less than the turbo-equivalent power limit.16. The system of any one of claims 11-15, wherein said dynamic responsemodel is determined by the hybrid controller using infinite impulseresponse filtering.
 17. The system of any one of claims 11-16, whereinsaid dynamic response model is represented discreetly by the equation:y([n+1]T _(s))=αy(nT _(s))+k(1−α)u(nT _(s)) where T is a constant, k isa constant, ${\alpha = e^{- \frac{T_{s}}{T}}},$ T_(s) is a discretesample time, y([n+1]T_(s)) is the turbo-equivalent output power of then+1 iteration, y(nT_(s)) is the turbo-equivalent output power value ofthe n iteration, and u(nT_(s)) is the current engine power of the niteration.
 18. The system of claim 17, wherein T and k are adaptivelydetermined by the hybrid controller using infinite impulse responsefiltering.
 19. The system of any one of claims 11-18, wherein said zeroboost power limit is determined by the hybrid controller by monitoringthe maximum available torque of the engine while the engine is idling,said maximum available torque received by the hybrid controller from theengine controller.
 20. The system of any one of claims 11-19, whereinsaid zero boost power limit is determined by multiplying a currentengine speed received from the controller by the average of the maximumavailable torque of the engine when idling.
 21. A hybrid system,comprising: an engine having a turbocharger; an engine controlleroperatively coupled to the engine; an eMachine; a hybrid controlleroperatively coupled to the eMachine and in communication with the enginecontroller; wherein the hybrid controller is configured to: receive adriver output torque request from said engine controller; and operatethe hybrid vehicle such that the collective output power of the engineand an eMachine of the hybrid vehicle is automatically limited to aturbo-equivalent power limit corresponding to said driver output torquerequest, said turbo-equivalent power limit representing the power limitof the engine acting alone.
 22. The hybrid system of any one of claims11-21, wherein the hybrid controller and the engine controller comprisea single controller.
 23. The hybrid system of any one of claims 11-22,wherein the hybrid controller and the engine controller are contained ina common housing.
 24. The hybrid system of any one of claims 11-23,wherein the hybrid controller is further configured to: determine a zeroboost power limit of the engine; receive torque curve information fromthe engine controller; determine a torque curve power limit of theengine from said torque curve information; monitor a current power ofthe engine and a maximum available power of the engine when the maximumavailable power is between the zero boost power limit and the torquecurve power limit; determine a dynamic response model of the enginebased on said monitoring, said model providing an estimation of theengine output power over time as the turbocharger increases in speed;use the dynamic response model to determine said turbo-equivalent powerlimit.
 25. The system of any one of claims 21-24, wherein the hybridcontroller is further configured to: receive an actual engine torque anda current engine speed from the engine controller; multiply said actualengine torque by said current engine speed to determine a current enginepower; determine an eMachine torque of the eMachine; multiply saideMachine torque by a current eMachine speed of the eMachine to determinea current eMachine output power; add said current engine power and saideMachine power to determine a total propulsion power; and use the totalpropulsion power to determine the turbo-equivalent power limit using themodel.
 26. The system of any one of claims 24-25, wherein said dynamicresponse model is represented discreetly by the equation:y([n+1]T _(s))=αy(nT _(s))+k(1−α)u(nT _(s)) where T is a constant, k isa constant, ${\alpha = e^{- \frac{T_{s}}{T}}},$ T_(s) is a discretesample time, y([n+1]T_(s)) is the turbo-equivalent output power value ofthe n+1 iteration, y(nT_(s)) is the turbo-equivalent output power valueof the n iteration, and u(nT_(s)) is the current engine power of the niteration.
 27. The system of any one of claims 21-26, wherein thedynamic response model is determined using infinite impulse responsefiltering.
 28. The system of claim 27, wherein T and k are adaptivelydetermined by the hybrid controller using infinite impulse responsefiltering.
 29. The system of any one of claims 21-28, wherein said zeroboost power limit is determined by the hybrid controller by monitoringthe maximum available torque of the engine while the engine is idling,said maximum available torque received by the hybrid controller from theengine controller.
 30. The system of any one of claims 21-29, whereinsaid zero boost power limit is determined by multiplying a currentengine speed received from the controller by the average of the maximumavailable torque of the engine when idling.
 31. The system of any one ofclaims 21-30, wherein the hybrid controller is further configured to setthe turbo-equivalent power limit to a zero boost power limit if the zeroboost power limit is greater than said turbo-equivalent power limit. 32.The system of any one of claims 21-31, wherein the hybrid controller isfurther configured to set the turbo-equivalent power limit to a torquecurve power limit of the engine if the torque curve power limit is lessthan the turbo-equivalent power limit.
 33. A method of operating ahybrid vehicle using a hybrid controller, comprising: receiving a driveroutput torque request using the hybrid controller; and using the hybridcontroller, operating the hybrid vehicle such that the collective outputpower of an engine and an eMachine of the hybrid vehicle isautomatically limited to a turbo-equivalent power limit corresponding tosaid driver output torque request, said turbo-equivalent power limitrepresenting the power limit of the engine acting alone.
 34. The methodof claim 33, further comprising: determining a zero boost power limit ofan engine of the hybrid vehicle, said engine including a turbocharger;determining a torque curve power limit of the engine, said torque curvepower limit based upon the maximum available power when the turbochargeris operating at a predetermined level; monitoring a current power of theengine and a maximum available power of the engine when the maximumavailable power is between the zero boost power limit and the torquecurve power limit; determining a dynamic response model of the enginebased on said monitoring, said model providing an estimation of theengine output power over time as the turbocharger increases in speed;and using said model to determine said turbo-equivalent power limit. 35.The method of claim 33 or 34, further comprising: receiving an actualengine torque and a current engine speed using the hybrid controller;multiplying said actual engine torque by said current engine speed todetermine a current engine power; determining an eMachine torque of theeMachine; multiplying said eMachine torque by a current eMachine speedof the eMachine to determine a current eMachine output power; addingsaid current engine power and said eMachine power to determine a totalpropulsion power; and using the total propulsion power to determine theturbo-equivalent power limit using the model.
 36. The method of any oneof claims 33-35, wherein said dynamic response model is representeddiscreetly by the equation:y([n+1]T _(s))=αy(nT _(s))+k(1−α)u(nT _(s)) where T is a constant, k isa constant, ${\alpha = e^{- \frac{T_{s}}{T}}},$ T_(s) is a discretesample time, y([n+1]T_(s)) is the turbo-equivalent output power value ofthe n+1 iteration, y(nT_(s)) is the turbo-equivalent output power valueof the n iteration, and u(nT_(s)) is the current engine power of the niteration.
 37. The method of any one of claims 33-36, wherein saiddynamic response model is determined by the controller using infiniteimpulse response filtering.
 38. The system of claim 37, wherein T and kare adaptively determined by the hybrid controller using infiniteimpulse response filtering.
 39. The method of any one of claims 33-38,wherein the hybrid controller is further configured to set theturbo-equivalent power limit to a zero boost power limit if the zeroboost power limit is greater than said turbo-equivalent power limit. 40.The method of any one of claims 33-39, wherein the hybrid controller isfurther configured to set the turbo-equivalent power limit to a torquecurve power limit of the engine if the torque curve power limit is lessthan the turbo-equivalent power limit.
 41. The method of any on ofclaims 33-40, wherein said zero boost power limit is determined bymonitoring the maximum available torque of the engine while the engineis idling.
 42. The method of claim 41, wherein said zero boost powerlimit is determined by multiplying a current engine speed by the averageof the maximum available torque of the engine when idling.